Barcodes are the most common form of tagging used for tracking and identifying objects—whether e-waste or otherwise. But barcodes can convey very limited information since they encode a short bit string as a series of parallel bars in two colors. More recently, two dimensional (2D) matrices, commonly known as QR codes, have been developed and offer a significantly higher information density. The method of reading information from a barcode or a QR code requires the surface on which these codes are printed to be of a certain minimum size and essentially flat. This poses a serious limitation on the use of such codes.
Waste, especially electronic waste (e-waste) comes in all shapes and sizes which may not always be amenable to tagging by barcodes or QR codes. With increasingly stringent global regulations requiring manufacturers and waste disposal companies to track their waste, a better method for tagging and tracking objects is necessary.
Graphene, a 2D form of carbon, has been shown to have many special properties such as high mechanical stiffness, high elasticity, tunable band gap and excellent electron transport, potentially lending it to many interesting applications. Conventionally, graphene is obtained by physical exfoliation of graphite, but the method suffers from poor yield. Chemical methods such as chemical vapor deposition, chemical reduction of graphite oxide, liquid phase exfoliation of graphite, and self-assembly are being researched for large-scale synthesis of graphene.